Component Design
CIRIA C753 §16
Filter Drain Calculator
CIRIA C753 §16: filter drain hydraulic and treatment sizing.
1
Catchment & Type
2
Rainfall
3
Geometry
4
Design Check
5
Results
Step 1: Catchment Area & Drain Type
Fields marked * are required
Project Information
Contributing Surfaces
Total Catchment Area
0.00
Weighted Runoff Coefficient (C)
0.00
Effective Area (C × A)
0.00
Step 2: Rainfall Data
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Rainfall Intensity
SAAR (mm/year):
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Design Rainfall Intensity (mm/hr):
-
Design Flow Rate (l/s):
-
Step 3: Trench Geometry & Aggregate Properties
Trench Dimensions
Aggregate Properties
Collector Pipe Sizing
Pipe Capacity (Colebrook-White)
Pipe Velocity (m/s):
-
Pipe Capacity (l/s):
-
Long-Term Performance & Clearance
0.3–0.5: unmaintained; 0.7: maintained with annual vac sweep
Depth from trench bottom to water table
Storage Volume
Provided Storage (m³):
0.00
Step 4: Design Check & Sizing
Review the design checks below. All must pass (green) for a compliant design. Click "Auto-Size Length" to optimise trench length.
Volume Balance
Storm Duration:
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Inflow Volume (m³):
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Outflow Volume (m³):
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Required Storage (m³):
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Provided Storage (m³):
-
Design Checks
Click below to calculate the minimum trench length required to meet all design criteria.
Step 5: Design Results
Summary
Design Verification
Design Notes
Key Assumptions
- Uniform infiltration along trench length.
- Aggregate void ratio is consistent throughout fill depth.
- Pipe roughness derived from material-specific ks values.
- Minimum trench depth 0.6m per design requirements.
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